1. Field of the Invention
The present invention relates to an apparatus and a method for acquiring and reading optical codes, with indication of the result of the reading itself.
2. Description of the Prior Art
In this description and the following claims, by the expression “optical code”, bar codes, stacked codes, that is, with a plurality of stacked bar sequences, bidimensional codes, colour codes, and the like should be meant.
Moreover, by “acquisition of an optical code”, the whole of illumination (or scan) of the code with a light beam, detection of the light diffused by the code, and its transformation into electric signal is meant, while by “reading of an optical code”, the processing of the electric signal and its interpretation or decoding are meant.
Finally, by “indication of the reading result”, also the mere indication of the end of the reading, or of the unsuccessful reading attempt, is meant.
Known optical code acquisition and reading apparatuses, or briefly, readers, are essentially provided with a light source for generating a light beam which is projected onto the optical code to be read, for example through slits and lenses, herein in general referred to with the expression “illumination optics”, optical elements suitable to collect and focus the light diffused by the code, for example slits and lenses (in general referred to with the expression “receiving optics”), photosensitive elements on which the light collected by the receiving optics is focused, suitable to detect the light diffused by the code and to convert it into an electric signal reproducing as much accurately as possible the reflectance modulations of the elements making up the code, as well as processing means for interpreting or decoding the code so as to obtain the significant information contained in it, such as for example manufacturer, name of the specific product, production lot, price, etcetera.
The operation of reading a particular optical code can give negative results for various factors, among which the imperfection of the code due, for example, to damages to the label on which it is obtained, the distance between the reader and the code, or the maintenance of said distance during the scanning time. In addition, also when the code is correctly acquired, its decoding may be impossible because, for example, it does not fall within the categories of codes known by the reader. In any case, the operator needs to know whether the code has been decoded before proceeding to read another code.
These problems are especially severe in the case of the so-called manual or hand-held readers, of the gun type.
Thus, in optical-code readers, simple indication devices are known and currently used for indicating to the user that the particular aimed optical code has been decoded by the reader.
Said indication is normally generated using a light source made up of one or more light emitting diodes (LEDs) arranged in the reader body, in the proximity of the outer surface or inside it. Since in both cases the LED must be visible from the outside, the light emitted by the LED can be refracted and/or diffused so as to be more visible towards the operator. However, the image of the reader body usually is at the edges of the operator's field of view, whose look is focused on the optical code. This is particularly true for codes of small sizes, or for stacked codes, whose reading requires a precise movement of the hand. Thus, the perception of the lighting of the LED arranged into the reader body may not be immediate.
To improve the perception of the indication that the reading has occurred, also when the visual attention of the operator is not focused on the reader, the lighting of the LED is commonly accompanied by an acoustic signal, provided for example by an electromagnetic acoustic horn, commonly called buzzer, or beeper. However, also this provision is not totally satisfactory since the acoustic signal cannot be easily heard if the operation is carried out in a noisy environment or by an operator with auditory deficiency. Moreover, a frequently repeated acoustic signal may be annoying for the operator who must carry out very frequent readings and/or for a long time interval.
The European patent application N. 98830656.9 by the same Applicant, which represents a document of the prior art according to Art. 54(3) EPC, describes an optical device comprising at least one illuminating assembly active on a portion of the reading area along an emission optical path, wherein said at least one illuminating assembly comprises: a light source; a diaphragm having a predetermined shape for selecting a portion of the light generated by said source; and a converging lens arranged downstream of the diaphragm for collimating the shaped light coming from the diaphragm and projecting it onto the portion of reading area.
However, said device is intended for the aiming and the visual indication of the area in which the optical code is, while the above document does not provide for any indication on the use of such a device for indicating the result of the optical-code reading.